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Topic: Does the time of day you water mater? (Read 3241 times)

During periods where i'm watering once/dayI usually water either at 6:00a.m. or 7:00p.m. M-F because of my work schedule. Sat and Sun I can usually water whenever. I'm wondering do you think one time is better than the other? Theoretically, if you water in the evening the growing medium stays wet for a longer period of time.

It doesn't matter particularly when you water. However, evening watering is likely more effective.

My simplistic model is that the roots have a fixed capacity to adsorb water. During hot daytimes, the transpirational demands can exceed this capacity - it won't matter much if you add water, the tree will still tend toward dehydration. At night the tranpiration rate drops (below the root's water adsorption rate) and the tree rehydrates, ready for another day in the sun. If the plant/tree "always" wilts during the day, moving it to a shadier location is the only practical remedy - watering more will not do much of anything beneficial.

My watering schedule is largely determined by my work schedule. I water on a timer schedule when I'm not able to water by hand. The timers are run in the morning. Most of my hand watering is done in the morning, although I'll water later in the day if I am available instead of the timers. I prefer to water by hand, as I can use rain water, and when I use the timers, I am using well water. The timers are run thru overhead sprinklers, so I wouldn't want to run those late in the day and have problems with wet leaves at night.

I've read that some people think that watering in the morning is better as it doesn't shock the plants roots, as they are cooler in the morning, and the water temperature isn't so different than the soil temp. I have no realistic knowledge if this is true.

In a perfect world I would water in. He morning, and then related in ate afternoon, with time or the folage to dry, particularly if you have a dead air and/or fungus history. Just my thoughts, since I don't live in a perfect world and sometimes have to Water after dark

If you live in a dry climate (low humidity) and/or have your trees in an area with good air movement evening watering shouldn't be an issue. Long exposure (10-12 Hours or more) to excess moisture leads to increased opportunity for fungal growth, especially on species with sensitivity to fungal infections. You might think it is a myth, but you are incorrect.

Watering at around 5-6 am is considered ideal according to many nurserymen and women I know and I agree with them. When a plant "wakes up" in the morning, it's stomates open (in the leaves) releasing oxygen and water vapor. This creates a pressure gradient between the root system and the upper part of the plant called Turgor pressure allowing the plant to suck water vertically like a straw. I have a degree in horticulture, have watered plants via residential irrigation service jobs in high school, multiple greenhouse ranges in college, planned and executed watering programs for a wholesale grower for five years, etc etc. Nothing make me more crazy than people trying to blind others with science. . Trees in bonsai pots can dry out damn fast. I've been reprimanded for not watering a Shohin tree at the start of a watering round that dried out in less than an hour! Watering at night (say 8-10 pm) is not ideal in my opinion but every once in a while will not hurt anything. Rain clouds aren't on schedules . I have watered my bonsai a variety of inconvenient times but always "reset" my schedule by ASAP.

At Kouka-en, we water by checking every tree once a day during winter at 1 pm. Spring is 7 am, quick check at 11 am, 1 pm, and a quick check at 4 pm. Summer is essentially constant checking, but we know which trees dry out faster and so on. Fall is much like Spring. My sensei likes to water when a tree is what I called "Kouka-en Dry", or about an hour or two before the tree actually dries out visibly (Akadama or sphagnum moss color change). I don't fully agree with this practice but his rationale is if a tree gets a root issue or deficiency, that is "fixable" while dessication / death of branches is not.

"a plant "wakes up" in the morning, it's stomates open (in the leaves) releasing oxygen and water vapor. This creates a pressure gradient between the root system and the upper part of the plant called Turgor pressure allowing the plant to suck water vertically like a straw."

That has been the foundation on my watering practices ever since I heard a specialist explain the process a while ago. The later in the evening you water, the more water is going to sit in the root zone unnused. Doesn't mean you can't water in the late afternoon or even at night if there's a hot wind drying out the pots, but making a habit of evening or nighttime watering isn't ideal. This is the same reason that lawns shouldn't be watered near or after dark. The moisture that isn't used can set up conditions for fungal problems and other stuff.

In Summerville, South Carolina there lives a myth and it's name is fungus. We will have summer temps of 90+ degrees with close to 100% humidity. You would think a plant would not be able to wilt in those conditions but they do. And if I water and droplets stay on the leaves during midday, I will get leaf burn. I wish I lived where you do. My solution is to water by hand when I can and an automated system when I can't. But I use the drip irrigation system with tiny misters, and they are located just above the pot rims. Water gets into the pots but not on the leaves. It's not perfect but it keeps my work alive. The auto system runs 20 min. at dawn( adjusted for time of year) and 20 min. at 6:00 PM. My trees are in full shade at about 4:00 PM. Hope this helps you Rockm, and Owen thanks for the great explanation! Don.

Also, the "don't water in heat of summer day" is crap too.Water droplets do NOT become little magnifying glasses and cook your tree...

How many years experience watering potted trees do you base this revelation on?

8

My advice is based on my experiences. I am sure some people with fungal issues could make it worse by watering at night.I simply have never had a fungal issue that seemed to be attributed to night time watering.

I usually water in the evening during the work week because I can't squeeze it in while trying to get out the door to work. I haven't noticed any fungal problems, but I did notice lots of fungal issues on my lawn when I watered it at night.